Escapement mechanism



June 1942. p, F, GATTUSQ 2,286,403

ESCAPEMENT MECHANISM Filed May 1, 1940 Patented June 16, 1942 i EscAPEMENT MEcHANrsM Peter F. Gattuso, Chicago, Ill.,assignor to Woodstock Typewriter Company, Woodstock, Ill., a corporationl of Illinois Application May 1, 1940, Serial No. 332,787

1 Claim.

This invention relates to typewriters in general and particularly to escapement mechanism therefor.

The primary object of the present invention is the. provision of new and improved means, constructed and arranged. in a predetermined manner to absorb the impact and jar occurring during the operation of the typewriter and thereby resiliently bring a movable member to rest quickly but gently without excessive vibration or rebound.

Another object of .the invention resides in the provision of an improved shock absorbing element in the form of a resilient vshelf against which a movable part of the typewriter .escapementmechanism has abutting or contacting engagement to bring the partsv to resting position atV the conclusion of its movement and thereby overcome jars, noises, vibration and clashing of parts.

A more specific object of the invention is the provision of a bracket member,Y made of` flexible, resilient spring steel positioned adjacent an arm of a bell-crank part of typewriter escapement mechanism so that as an operating end of theA bell-crank approaches the end of its travel ,toward a limiting stop, thek bracket will be engaged `and cushion the blow, thereby preventing a direct hard blow against the stop and causing the part to come to rest silently and sof-tlywithout hindering the speed or operativeness of the said part.

Numerous other objects and advantages will be apparent throughout the progress of the following specification.

The accompanying drawing illustrates a selected embodiment of the present invention and the views therein are as follows:

Fig. 1 is a detail rear elevational view of escapement mechanism applied to a typewriter and embodying the invention, thev parts being shown in normal or rest position;

Fig. 2 is a view similar to Fig. l but showing the parts in an advanced position;

Fig. 3 is a detail perspective view of some of the escapement mechanism and embodying the invention; and

Fig. 4 is a detail perspective view of the shelf employed as the resilient stop member.

The particular mechanism herein shown to illustrate the invention is shown applied to the popular, well known Woodstock typewriter although the invention is susceptible for application to other makes of typewriters. The Woodstock typewriter herein illustrated in part comprises a typewriter frame 5, which is provided with rails upon which a carriage (not shown) is free to slide transversely.

A rack 6,' having the usual limited pivotal movement, and spring urged in a predetermined normal operating position,l is mounted on the carriage at the rear of the machine and moves transversely with the carriage. The carriage with its attached rack 6 is drawn toward the right, Fig. 1, by suitable resilient means, such as by a tape fastened to apart of the carriage and to a revolubly mounted' spring urged casing mounted on the typewriter frame. This resilient means is permitted to draw the carriage to the right, Fig. l, only when the escapement mechanism is released by the depressionof a key or the spacing bar, but the action tending normally to draw the carriage to the right is constant.

The resilient means tends to urge the carriage in a predetermined position, but the action of this resilient means on vthe carriage is retained or resisted by the rack 6 which is normally in engagement with a pinion I rotatably mounted about a pivot pin 8. The pinion 'l is free to rotate in a counter-clockwisedirection, as viewed in Figs. 1 and 2, but is held rigidly from movement in a clockwise direction by a pawl 9- normally maintained in engagement with the pinion. The pawl 9 is pivotally mounted at I0 on an escapement wheel Il which is mountedoperatively on the pivot pin 8, being arranged adjacentV the pinion 1 for proper co-operation therewith. A spring i2 cn the escapement wheel Il has engagement with the pawl 9 to hold the pawl in engagement with the pinionv 1. The pawl 9 is arranged so as to permit movement freely of the pinion 1 in a counter-clockwise direction, as viewed in Figs. 1 and 2, so that the carriage may be returned readily in the usual manner against the action of the aforementioned resilient means.

The escapement Wheel Il is provided with a plurality of outwardly extending peripheral teeth I3, equal to the number of teeth I4 on the pinion 1. In actual practice it has been found that sixteen teeth on the escapement wheel and pinion are very satisfactory to the proper performance and operation of the machine. The escapement wheel Il may include an integral sleeve formed therewith and arranged about the pivot pin 8, and the pinion 'l may be rotatively mounted on this sleeve. The escapement wheel Il and the pinion 1 may be retained in assembled relationship by a set screw threadedly engaging the pivot pin 8, and the pivot pin 8 may be operatively supported in a bore provided in the machine frame in a, manner Well known in the art.

The remainder of the escapement mechanism is of Well known construction and includes a supporting bracket member I5 which is supported at I6 and I1 between pivot bearings I8 and I9 threadedly mounted in opposed rigid projections and 2| on the machine frame 5. A space link operated by the spacing bar may be operatively connected to a part 22 on the bracket I5 to tilt the supporting bracket I5 from front to rear so as to disengage a movable stop dog 23 from a tooth I3 on the escapement Wheel, Immediately upon movement of the dog 23 from a tooth I 3, the resilient means pulls the carriage until the freed tooth I3 engages the xed dog 24. Upon release of the spacing bar, the bracket I5 will return to its normal position whereby the tooth I3 will be freed from the fixed dog 24, and the next succeeding tooth I3 will be at rest against the movable dog 23. The tilting or pivotal movement of bracket I5 is also accomplished by the depression of a key; the key having an operative connection with a frame 25 pivoted on pins 26, and having a part engageable with the bracket I 5 to tilt the bracket and permit the escapement which is referred to above.

The dog 23 comprises a bell-crank 21 which is pivoted at 2B to the bracket I5. An arm of the bell-crank, which is the movable dog 23, is engageable with the teeth I3 on the escapement wheel II. The other arm 29 of the bell-crank 21 has a spring 3B fastened thereto, tending to urge the bell-crank about its pivot 28 toward a xed stop pin 33. rlhe bell-crank 21 has a striking face or stop abutment 32 adapted for engagement with another stop pin 3 I. The bellcrank 21 has its upper arm (the dog 23) positioned between the stop pin 3| and the stop pin 33, whereby the lateral movement of dog 23 is limited.

The fixed dog 24 is fastened to the bracket I5 by a fastening member 36, the stern of which passes through a slot 35 in the bracket I5 to permit adjustment of the fixed dog 24.

The striking of the teeth I3 on the escapement wheel II, against the dog 23, shifts the dog 23 on its pivot to the left, Figs. l and 2, causing the face 32 to move toward the stop pin 3|. The direct contact of the face 32 against the pin 3| would set up a vibration as well as a clashing sound or noise each time a key or the space bar was released after being rst depressed. To overcome these disadvantages, resilient means is provided to retard the movement of the dog 23 just prior to the time the striking face hits against the stop pin 3|. This resilient means comprises a bracket or angle member 36, Fig. 4, made of stiff spring steel and having its upper leg or arm 31 fixed to the bracket I5 and its lateral leg 38 extending outwardly, as viewed in Figs. 1 and 2, so as to be engaged by the arm 29 of the bellcrank 21 during its pivotal movement to the left, Figs. 1 and 2. The shelf presented by the leg 38 therefore cushions the blow of the bellcrank 21 before the face 32 strikes the stop pin The cushioning of the dog therefore reduces vibrations to a minimum, and overcomes any noises which would be caused by the clashing and direct striking of rigid parts.

The invention therefore provides a new and novel arrangement of parts to overcome and reduce noises and vibrations to a minimum. The cushioning element 36, while relatively small and appearing insignieant provides just the proper amount of cushioning necessary because of its particular location, construction and the kind of material from which it is made. The element may be applied to existing typewriters as Well as to new constructions. The parts are constructed and arranged to Vperform the proper function at precisely the proper time; moreover, it has been found in actual practice that wear on the parts is lessened, and because of the elimination of shock and jar the typewriter does not become noisy after extended use. Furthermore, the strain on the operator is lessened because noise is reduced and considerable vibration is eliminated.

Changes may be made in the form, construction and arrangement of the parts Without departing from the spirit of the invention or sacricing any of its advantages and the right is hereby reserved to make all such changes as fairly fall within the scope of the following claim.

The invention is hereby claimed as follows:

Escapement mechanism for typewriters comprising a pivotally mounted bracket, aAbell-crank pivotally mounted on the bracket, means to move the bell-crank, stop means on the bracket on each side of the bell-crank to limit the movement thereof, one part of the bell-crank adapted for engagement with teeth on an escapement wheel to hold the wheel, and an angle bracket of L- shape and formed of spring metal fixed to the bracket by one leg and having its other leg freely projecting outwardly therefrom into the path of movement of one arm of said bell-crank to form a shelf against which said arm of the bellcrank engages as the ,bell-crank moves toward one of said stop means to cushion the bell-crank movement and prevent the bell-crank from striking the stop means a hard blow.

PETER F. GAT'I'USO. 

